When her 23-year-old son was murdered, stabbed seven times by a stranger on a French Quarter street corner, Lucy Lekosky believed she might never know who had killed him. For six weeks, she couldn't sleep, as her son's killer remained unknown.

"I've actually slept well these last two nights," she said Friday, more than two years later and just after a New Orleans jury convicted 39-year-old Melvin Clay of the second-degree murder of her son, a decorated Marine. "It's a little bit of closure."

After a weeklong trial, the jury dismissed Clay's claims of self-defense. His attorney, John Thomas, said he knew it would be a hard case to make. In order to make a jury buy an argument of self defense, a defendant has to testify. And Clay is a self-described gigolo and an accused pimp with a long history of gang-related and drug convictions -- all of which were presented to the jury when he took the witness stand Thursday.

In November 2010, Kristen Lekosky, the widow of Marine Corps Sgt. Ryan Lekosky, leaves the chapel after a memorial service for her husband at the Naval Air Station-Joint Reserve Base Chapel in Belle Chasse. Ted Jackson, NOLA.com | The Times-Picayune

In his closing argument to the jury, Assistant District Attorney John Alford asked jurors to consider the character of both men involved.

Clay is a lifelong criminal, he said. Sgt. Ryan Lekosky, was a decorated Marine, a veteran of Iraq, strolling the French Quarter streets with his new wife.

But Thomas argued that the pasts of these two strangers mattered little in the decision the jury had before them. "We have the same system of justice for everybody," he said.

His client had, admittedly, killed Lekosky early on the morning of Oct. 31, 2010. But he argued it was a justifiable homicide under the state's stand-your-ground law, which allows someone to use deadly force to protect himself from intruders. Clay testified that he was attacked by the Marine's wife, who he said lunged into his car window, grabbed his knife from the floorboard, then threw the first punch. He didn't stab the Marine, he claimed, rather he flailed the knife wildly and slashed the Marine by accident.

But prosecutors -- with a parade of witness and grainy, largely indiscernible video from nearby security cameras -- described a very different scene.

It was Halloween night 2010; the Quarter was crowded with cars and costumed pedestrians.

Clay said he had been to an eastern New Orleans strip club, then headed to the Quarter to joyride and catcall women. He passed by Lekosky and his wife, Kristen, walking near the corner of Iberville and Dauphine streets around 3:30 a.m.

The Lekoskys had been to the Marine Corps Ball, then they visited a few bars in the French Quarter. Lekosky, a native Texan, was in his dress blues; his wife was wearing a green cocktail dress and high-heeled shoes.

Prosecutors alleged, and Kristen Lekosky testified, that Clay shouted vulgar comments at her. He claimed he was talked to other women -- one dressed as a bumble bee and another as a cheerleader, both of whom responded amicably to his remarks.

But Kristen Lekosky believed he was speaking to her and confronted him verbally. The two argued. Clay claimed that the woman assaulted him through the window of his car -- a key requirement to support his claim of justifiable homicide. The law extends protection to those who kill when in fear of bodily harm, or when someone intrudes into their home or car.

The state, though, alleged that Clay started the physical fight. He got out of the car, without reasonable provocation and with his knife at the ready, and approached Kristen Lekosky. He pushed her down. Her husband helped her to her feet, then tried to wedge himself between his wife and the stranger. Clay stabbed the Marine with seven short jabs -- clean cuts, not wild swipes as Clay had claimed.

Marine Corps Sgt. Ryan Lekosky, a native Texan who was stabbed to death in the French Quarter on Halloween night 2010, after attending the Marine Corps Ball with his wife. Ted Jackson, NOLA.com | The Times-Picayune

Clay jumped back into his SUV, sideswiping two cars as he sped away. Meanwhile, Ryan Lekosky lay dying on the sidewalk. His bloody dress blues and blood-stained service pins were introduced into evidence at trial, despite defense protests that they were meant solely to shock the jury.

In fact, Clay might never have been caught, as Lucy Lekosky had feared.

It was a small piece of evidence -- the back plate off his side-view mirror that snapped off when he clipped a parked car as he made his getaway -- that eventually led NOPD Detective Andrew Packer to a Houston rental car company. Clay had returned the vehicle, said the damage was caused when he hit a gas pump, then came back to the rental agency and requested to rent the same vehicle again.

He was caught, in New Orleans, with 23-year-old Helaina Amrine. Amrine was charged with obstruction of justice and accessory after the fact. The two originally told police they were longtime lovers. But Amrine, who was offered a plea deal for no more than five years, testified at Clay's trial that she was a prostitute and he was her pimp.

Clay had called her the morning of the murder, she said. He told her he had been in a fight and to pack up and leave if he didn't return to their motel in an hour. When he did return, wearing a bloody shirt, he told her he'd broken his switchblade knife, and had thrown the pieces out on the interstate.

The pair eventually left town and returned to Clay's hometown of Houston, where he sent Amrine into a drug store to buy lighter fluid. He burned his bloody clothes and shoes in the backyard of his mother's house, while she watched, she told the jury.

Prosecutors described Clay's self-defense argument as the last act of a desperate man. At first, he claimed in conversations with his sister from the jailhouse phone -- recordings of the calls were played for the jury -- that he had never been there, had never stabbed a Marine.

But, with Amrine working against him, Clay could no longer plead mistaken identity, prosecutors suggested, so he opted for self defense instead. Why would a man, acting only to save his life, destroy evidence, cross state lines and never tell a soul he'd been attacked, they questioned.

Clay testified Thursday that he'd consulted a minister, who told him that God's law is different from man's law, and he didn't have to turn himself in, in penance for killing another person.

Meanwhile, Lekosky's mother, his new wife, his siblings and his fellow Marines were left to wonder whether his killer would ever be caught. "Siblings buried a brother, a father and mother buried a son, a wife buried a husband and this country buried a soldier," Alford said in his closing argument Friday. "All because this man is a murderer."

Melvin Clay, left, and Helaina Amrine were charged in connection with the murder of Marine Corps Sergeant Ryan Lekosky in the French Quarter in October 2010.Orleans Parish Sheriff's Office

District Attorney Leon Cannizzaro joined the Lekosky family on the courthouse steps Friday after the verdict was read, thanked the family for their courage and said he was pleased to have permanently taken a dangerous man off the streets.

Clay's victim, the Marine sergeant, was a funny, friendly young man of courage and character, his friends and family said. He was always the first to take new recruits under his wing, said Maj. Dameon Green, who was Lekosky's supervisor at the Naval Air Station-Joint Reserve Base in Belle Chasse. Theirs was a small squadron, a half-dozen Marines in total, and his death hit them all hard. In the years since, he said, he's thought often of Lekosky's family and the toll the looming trial must have taken on them.

"It angered me tremendously," Green said. "I'm elated today about the result. But I do miss him. He was a great kid, a great Marine."

The jury -- seven women and five men -- deliberated less than four hours before finding Clay guilty as charged of second-degree murder and obstruction of justice, for destroying evidence of the crime. He is facing a mandatory life sentence, which presiding Judge Ben Willard will impose on Jan. 25.

Lekosky's mother left the courthouse Friday, weeping and clinging to her surviving children, and said that she might finally get some peace. "I had 23 years with him, and I'm just glad I had those 23 years," she said. "We left nothing unsaid."